Quick question and a video from my XK8 with 117k miles. The past few weeks, it's make a quick grinding or chirping sound immediately upon start up. It lasts 1-2 seconds and then is gone as the engine sounds normal.

Last week my thermostat stuck and I replaced it. The engine cooling fans seem to be on a lot more than normal.

My question is, does this sound like the water pump has disintegrate or is the started bad? It only occurs on start up. The first video is the normal quick "chirp."




The second video is what happened this morning. The chirping has never made the noise for this long.


Please listen and let me know what you think!

Thanks in advance!!

 

In the second video I hear two hammer sounds after starting...that sounds like the belt tensioner snapping. You can acually see that if you have someone start the car and watch the tensioner with a bright light. That is usually caused by a failing bearing in one of the idler pulleys, but could also be one of the other rotating accessories.

If your engine cooling fans are still on more, a water pump check is advisable (and be sure the new thermostat is not installed reversed).

 

Thanks for the info. I thought the '01 had the better timing chain tensioner that didn't need replacing like the plastic ones for the earlier XK-8s. Am I wrong?

 

I was talking about the BELT tensioner on the outside of the engine regarding the hammer like knocking in the second video.

As far as the internal TIMING CHAIN secondary tensioner goes, you should be very concerned if it has not been updated with your mileage. That may very well be the source of the startup rattle. The improved ones were changed over in LATE '01 and most '01 models DO NOT have them.

I suggest having your secondary tensioners inspected ASAP and do not drive any more until you do.